--- a/dom/events/VirtualKeyCodeList.h
+++ b/dom/events/VirtualKeyCodeList.h
@@ -207,16 +207,19 @@ DEFINE_VK_INTERNAL(_BACK_SLASH)
 DEFINE_VK_INTERNAL(_CLOSE_BRACKET)
 DEFINE_VK_INTERNAL(_QUOTE)
 
 DEFINE_VK_INTERNAL(_META)
 DEFINE_VK_INTERNAL(_ALTGR)
 
 DEFINE_VK_INTERNAL(_WIN_ICO_HELP)
 DEFINE_VK_INTERNAL(_WIN_ICO_00)
+
+DEFINE_VK_INTERNAL(_PROCESSKEY)
+
 DEFINE_VK_INTERNAL(_WIN_ICO_CLEAR)
 DEFINE_VK_INTERNAL(_WIN_OEM_RESET)
 DEFINE_VK_INTERNAL(_WIN_OEM_JUMP)
 DEFINE_VK_INTERNAL(_WIN_OEM_PA1)
 DEFINE_VK_INTERNAL(_WIN_OEM_PA2)
 DEFINE_VK_INTERNAL(_WIN_OEM_PA3)
 DEFINE_VK_INTERNAL(_WIN_OEM_WSCTRL)
 DEFINE_VK_INTERNAL(_WIN_OEM_CUSEL)

--- a/dom/webidl/KeyEvent.webidl
+++ b/dom/webidl/KeyEvent.webidl
@@ -190,16 +190,22 @@ interface KeyEvent
 
   const unsigned long DOM_VK_META           = 0xE0;
   const unsigned long DOM_VK_ALTGR          = 0xE1;
 
   // OEM specific virtual keyCode of Windows should pass through DOM keyCode
   // for compatibility with the other web browsers on Windows.
   const unsigned long DOM_VK_WIN_ICO_HELP    = 0xE3;
   const unsigned long DOM_VK_WIN_ICO_00      = 0xE4;
+
+  // IME processed key.
+  const unsigned long DOM_VK_PROCESSKEY      = 0xE5;
+
+  // OEM specific virtual keyCode of Windows should pass through DOM keyCode
+  // for compatibility with the other web browsers on Windows.
   const unsigned long DOM_VK_WIN_ICO_CLEAR   = 0xE6;
   const unsigned long DOM_VK_WIN_OEM_RESET   = 0xE9;
   const unsigned long DOM_VK_WIN_OEM_JUMP    = 0xEA;
   const unsigned long DOM_VK_WIN_OEM_PA1     = 0xEB;
   const unsigned long DOM_VK_WIN_OEM_PA2     = 0xEC;
   const unsigned long DOM_VK_WIN_OEM_PA3     = 0xED;
   const unsigned long DOM_VK_WIN_OEM_WSCTRL  = 0xEE;
   const unsigned long DOM_VK_WIN_OEM_CUSEL   = 0xEF;